Gas splitting by time average injection into different zones by fast gas valves

ABSTRACT

Techniques are disclosed for methods and apparatuses for delivering process gas for processing a substrate. In one embodiment, the method begins by injecting process gas into a processing chamber proximate an edge of a substrate disposed in the processing chamber from a first location. The method then continues by way of injecting the process gas into the processing chamber proximate the edge of the substrate disposed in the processing chamber from a second location while no gas is injected from the first location. Finally, the method finishes by way of processing the substrate in the presence of the processing gas injected from the first and second location.

BACKGROUND

Field

Embodiments described herein generally relate to semiconductormanufacturing and more particularly to a method and apparatus forproviding process gases for processing a semiconductor substrate.

Description of the Related Art

During the manufacture of semiconductor devices, a substrate may undergomultiple operations in a variety of processing chambers, or even asingle processing chamber, for the purpose of forming material layersand features suitable for an end use. For example, the substrate mayundergo several depositions, annealing, and etching operations, amongother operations.

Device miniaturization has made small dimensions for device patternsformed in a film layer of the substrate more critical. Achieving thecritical dimensions in the substrate begins with a good quality filmlayer having good adhesion to the underlying film layers in thesubstrate. Forming vias and other high quality closely packed featuresin the substrate may require processes utilizing multiple gases during asingle operation. For example, the formation of deep vias may requireprecise control of process gas flows into the processing chamber foretching as well as forming protective polymerization layers for ensuringthe deep vias have substantially vertical sidewalls. Maintaining goodcontrol for the delivery of the process gases during processing promotesprocess uniformity in forming the quality device features.

Gas delivery systems used with semiconductor processing chambersgenerally include either a mass gas flow meter (MFC) as the primary flowregulation device or a system of fast valves for fast gas exchange. Gasdelivery systems with fast evacuation paths enable a plurality ofprocessing gases to be supplied from the gas delivery systems into theprocessing system with a stable gas flow and minimum fluctuation. Thefast gas exchange systems use a plurality of orifices, or choke points,to tune the flow paths for controlling the flow of the different processgases. However, the fast gas exchange systems are a complicated systemof orifices and valves which take up considerable real estate and arecostly to implement and maintain.

Therefore, there is a need for a low cost and effective gas deliverysystem for controlling the delivery of process gases to a processingsystem.

SUMMARY

Techniques are disclosed for methods and apparatuses for a gas deliveryassembly and for processing a substrate with said gas delivery assembly.In one embodiment, the method begins by injecting process gas into aprocessing chamber proximate an edge of a substrate disposed in theprocessing chamber from a first location. The method then continues byway of injecting the process gas into the processing chamber proximatethe edge of the substrate disposed in the processing chamber from asecond location while no gas is injected from the first location.Finally, the method finishes by way of processing the substrate in thepresence of the processing gas injected from the first and secondlocation.

In another embodiment, a processing chamber has a plurality of walls, abottom, and a lid. The plurality of walls, the bottom and the lid defineand interior volume. A substrate support is disposed in the interiorvolume. The substrate support has a top surface configured to support asubstrate thereon. The processing chamber additionally has a gasdelivery assembly. The gas delivery assembly has a gas manifold disposedoutside the interior volume of the processing chamber. The gas deliveryassembly additionally is coupled to two or more gas nozzles positionedto deliver gas into the interior volume from the gas manifold. Gaspassageways extend from the gas manifold to the two or more gas nozzles,wherein each gas passageway has substantially the same conductance.

In yet another embodiment, a method is provided for processing asubstrate in a processing chamber having a plurality of spaced apart offcenter nozzles. The method begins by injecting a process gas from afirst nozzle into the processing chamber proximate an edge of thesubstrate disposed in the processing chamber. The method then continuesby way of injecting the process gas from a second nozzle into theprocessing chamber proximate the edge of the substrate disposed in theprocessing chamber while no gas is injected from the first nozzle. Themethod continues by way of injecting the process gas from a third nozzleinto the processing chamber proximate the edge of the substrate disposedin the processing chamber while no gas is injected from the first nozzleor second nozzle. The method further continues by way of injecting theprocess gas from a fourth nozzle into the processing chamber proximatethe edge of the substrate disposed in the processing chamber while nogas is injected from the first nozzle, second nozzle, or third nozzle.The method repeats by sequencing around the nozzles.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentdisclosure can be understood in detail, a more particular description ofthe disclosure, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlyexemplary embodiments and are therefore not to be considered limiting ofits scope, and may admit to other equally effective embodiments.

FIG. 1 is a side schematic view of an example process chamber having agas delivery assembly.

FIG. 2 is a top schematic diagram depicting a substrate disposed in theprocessing chamber of FIG. 1 interfaced with the gas delivery assembly.

FIG. 3 is a block diagram for a method for processing a substrate.

Additional features and advantages will be set forth in the detaileddescription which follows, and in part will be readily apparent to thoseskilled in the art from that description or recognized by practicing theembodiments as described herein, including the detailed description thatfollows, the claims, as well as the appended drawings.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements and features of oneembodiment may be beneficially incorporated in other embodiments withoutfurther recitation.

DETAILED DESCRIPTION

Reference will now be made in detail to the embodiments, examples ofwhich are illustrated in the accompanying drawings, in which some, butnot all embodiments are shown. Indeed, the concepts may be embodied inmany different forms and should not be construed as limiting herein.Whenever possible, like reference numbers will be used to refer to likecomponents or parts.

Embodiments disclosed herein include a gas delivery assembly and amethod for using the same. The gas delivery assembly may be deployed inprocessing chambers using multiple process gases, such as types ofprocessing plasma chambers, for example plasma treatment chambers,physical vapor deposition chambers, chemical vapor deposition chambers,high density plasma chemical vapor deposition (HDPCVD) chambers,low-pressure chemical vapor deposition (LPCVD) chambers, among others,as well as other systems where the ability to control processinguniformity for a features formed in a substrate is desirable. The gasdelivery assembly enables quick switching of process gases for betterprocess control at a significant cost reduction compared to conventionalflow splitting gas delivery systems.

FIG. 1 is a front schematic view of a processing chamber 100 having agas delivery assembly 180. The processing chamber 100 shown in FIG. 1 isconfigured as an etch chamber. However, it should be appreciated thatthe gas delivery assembly 180 may be utilized in a chemical vapordeposition (CVD) processing chamber, hot wire chemical vapor deposition(HWCVD) processing chamber, physical vapor deposition chamber, or otherprocessing chamber for processing substrates therein. In one embodiment,the processing chamber 100 is a high density plasma chemical vapordeposition (HDPCVD) chamber.

The processing chamber 100 includes a chamber body 102 having a top 122,chamber sidewalls 104 and a chamber bottom 108. The chamber body 102 iscoupled to a ground 126. The top 122, the chamber sidewalls 104 and thechamber bottom 108 define an interior volume 140. The chamber sidewalls104 may include a substrate transfer port 116 to facilitate transferringa substrate 118 into and out of the processing chamber 100. Thesubstrate transfer port 116 may be coupled to a transfer chamber and/orother chambers of a substrate processing system.

A pumping port 191 may be formed in the chamber bottom 108 or thechamber sidewall 104. A pumping device (not shown) is coupled to thepumping port 191 to evacuate and control the pressure within theinterior volume 140 of the processing chamber 100. The pumping devicemay be a conventional roughing pump, roots blower, turbo pump or othersimilar device that is adapted control the pressure in the interiorvolume 140.

A pedestal 134 for holding the substrate 118 may be disposed in theinterior volume 140. The pedestal 134 may be supported by the chambersidewall 104 or chamber bottom 108. The pedestal 134 may have coolingfluid channels and other conventional features. The pedestal 134 mayinclude a substrate support 132. The substrate support 132 may be aheater, suscepter, vacuum chuck, electrostatic chuck (ESC) or othersuitable structure for supporting or chucking the substrate 118 to thepedestal 134 during processing. The substrate support 132 may include achucking electrode 136 connected to a chucking power source 138. Thesubstrate support 132 may additionally, or alternately, include a heaterelectrode 142 connected through a match circuit 144 to a heater powersource 148. The substrate support 132 may use electro-static attractionto hold the substrate 118 to the substrate support 132 and apply heat tothe substrate 118 during processing in the processing chamber 100.

A top coil 128 and/or a side coil (not shown) may be disposed on thechamber body 102 of the processing chamber 100. The top coil 128 may beconnected to one or more RF power sources 126. The top coil 128 inducesan electromagnetic field in the interior volume 140 for maintaining aplasma formed from process gasses.

A system controller 160 may operate the processing chamber 100. Thesystem controller 160 includes a central processing unit (CPU) 162,system memory 164, and an input/output interface 166 all incommunication via a bus path. CPU 162 may include one or more processingcores. The system memory 164 stores a software applications, and data,for use by CPU 162. Input from one or more user input devices (e.g.,sensors, keyboard, mouse, touch screens, still or video cameras, motionsensors, and/or other devices) provided input and instructions to thesystem controller 160. The system controller 160 controls andcoordinates the operations of the processing chamber 100.

The gas delivery assembly 180 provides process and other gases into theinterior processing volume 140 of the processing chamber 100. The gasdelivery assembly 180 includes a gas panel 184, a gas manifold 182, gaspassageways 185, and fast acting valves 120. The gas delivery assembly180 is coupled to nozzles 114 positioned to deliver gas from the gasdelivery assembly 180 into the interior volume 140 of the processingchamber 100. The gas delivery assembly 180 may also include a tuning gassource 188.

The gas panel 184 supplies process and other gases through a gas line187 to the gas manifold 182. A mass flow controller (MFC) 183 may bedisposed on the gas line 187 for regulating the flow of individual gasesfrom the gas panel 184 into the gas manifold 182. The gas panel 184 maybe configured to provide one or more process gases, inert gases,non-reactive gases, reactive gases, or cleaning gases if desired.Examples of process gases that may be provided by the gas panel 184include, but are not limited to, sulfur hexafluoride (SF₆),trifluoromethane (CHF₃), a silicon (Si) containing gases, carbonprecursors and nitrogen containing gases. In one embodiment, the gaspanel 184 provides an etchant gas such as sulfur hexafluoride (SF₆) intothe manifold 182.

Additionally, the tuning gas source 188 may be fluidly coupled to themanifold 182 through a flow controller, such as a mass flow controller(MFC) 186. The tuning gas source 188 may source may provide oxygen (O₂),chlorine (Cl2), silane (SiH₄), hydrogen (H), or other suitable gas. TheMFC 186 regulates the flow of the tuning gas entering into the manifold182 from the tuning gas source 188. The MFC 186 is configured to operateat a rapid frequency between a flow and non-flow states. For example,the MFC 186 operates to enable the gas flow states to be changed betweena flow condition and a non-flow condition at a frequency of betweenabout 0.1 and 0.5 seconds. The rapid switching frequency enablesinjection of the tuning gas into the manifold 182 to be directed to asingle location in the processing chamber, as discussed below withregard to how the flow of gas is sequenced through the nozzles 114.

The manifold 182 is coupled to each of the nozzles 114 by a respectivegas passageway 185. The flow through each nozzle 114 is controlled by afast acting valve 120. Some or all of the nozzles 114 may be equallyspaced about the substrate support 132 to promote uniformity of gas flowacross the substrate 118. In one embodiment, the processing chamber 100may have four nozzles 114 disposed about the perimeter of the substratesupport 132. In another embodiment, an additional nozzle 114 may bepositioned at a central location of the lid 122 and directs gas downwardto the center of the substrate support 132.

FIG. 2 is a schematic diagram of a substrate disposed in the processingchamber 100 of FIG. 1 interfaced with the gas delivery assembly 180. Thegas delivery assembly 180 is shown removed from the processing chamber100 while depicting the substrate 118 to shown potential configurationsfor the nozzles 114 are positioned around an outer edge 206 of thesubstrate 118, and one nozzle 114 positioned over the center of thesubstrate 118. Although FIG. 2 illustrates 5 nozzles 114, along withcorresponding gas passageways 185 and fast acting valves 120, it iscontemplated that the processing chamber 100 may have otherconfigurations with two or more nozzles 114.

In one embodiment, a configuration of two nozzles 114 is described. Thegas delivery assembly 180 has a first nozzle 114-1 corresponding to afirst location and a third nozzle 114-3 corresponding to a secondlocation. The gas manifold 182 is fluidly attached to the first nozzle114-1 by a first gas passageway 185-1 through a first fast acting valve120-1. The gas manifold 182 is also fluidly attached to the third nozzle114-3 by a third gas passageway 185-3 through a third fast acting valve120-3. The nozzles 114 are adjacent to and may be part of or directlycoupled to the fast acting valves 120. Thus, the fast acting valves120-1, 120-3 are disposed adjacent the walls of the processing chamber.The fast acting valves 120-1, 120-3 are individually controlled and thefirst fast acting valve 120-1 is closed when the second fast actingvalve 120-3 is in an open state. Similarly, the second fast acting valve120-3 is closed when the first fast acting valve 120-1 is in an openstate. The first and third gas passageway 185-1, 185-3 have asubstantially similar high conductance. Thus, pressure of the processgas at the first and second fast acting valves 120-1, 120-3 aresubstantially the same. Additionally, the gas pressure at the nozzles114-1, 114-3, having their respective first or second fast acting valve120-1, 120-3 in an open state, is substantially similar to the gaspressure in the first and third gas passageway 185-1, 185-3.

In a second embodiment, a configuration of four nozzles 114 is depicted.The gas delivery assembly 180 has in addition to the first nozzle 114-1at the first location and a third nozzle 114-3 corresponding now to athird location, a second nozzle 114-2, valve 120-2 and passageway 185-2corresponding to the second location and a fourth nozzle 114-4, valve120-4 and passageway 185-4 corresponding to a fourth location. Each gaspassageway 185-1, 185-2, 185-3, 185-4 has substantially similar highconductance and is configured to provide a pressure in the gaspassageway 185-1, 185-2, 185-3, 185-4 substantially similar to apressure in the manifold 182 when a gas is flowing through a respectivethe gas passageway 185-1, 185-2, 185-3, 185-4.

In a third embodiment, a configuration of three nozzles 114 may besimilarly described with the nozzles 114 spaced substantiallyequidistant apart. In a fourth embodiment, a five nozzle 114configuration may be similarly described similarly to the secondembodiment with the addition of a fifth center nozzle 114-5 disposed ata center location 114-5. The gas manifold 182 is fluidly coupled by thefifth gas passageway 185-5 to the fifth center nozzle 114-5 through afifth fast acting valve 120-5. Thus, it can be plainly seen that anyconfiguration of no

The gas delivery assembly 180 may also have one or more mass flowcontrollers 183, 186 configured to provide a gas into the gas manifold182. The gas manifold 182 may contain process or other gases sufficientin volume for distribution into the processing chamber during a singlecycle for one of the fast acting valves 120. A cycle of one fast actingvale 120 disposed on each of the gas passageways 185, may operatebetween an open and a closed state in less than 10 milliseconds. Thefast acting valves are rated for 10 Million cycles or more and a flowrate of between about 10 SCCM and 5000 SCCM.

The process gas flows through each of the nozzles 114-1, 114-2, 114-3,114-4, 114-5 one at a time. Thus, when process gas is flowing throughthe first nozzle 114-1, no process gas is flowing through the second,third, fourth, or fifth nozzle 114-2, 114-3, 114-4, 114-5. The processgas flowing through the nozzle 114 is drawn over the top surface of thesubstrate 118, or substrate support 132, with the aid of the pressure inthe gas passageways 185 and additionally, the vacuum pump. As seen inFIG. 1, the vacuum is drawing from around the bottom of the substratesupport 132. The nozzle 114 injects the process gas toward the center204. The vacuum may draw the process gas across the top of the substratesupport 132 past the center 204. In this manner, the gas deliveryassembly 180 ensures there is no dead zone present in the center 204 asfound in conventional fast gas systems.

The fast acting valves 120 may be configured and sequenced to provideprocess gases to various zones of the substrate 118 undergoingprocessing with the supplied process gas. The process may be tuned toincrease or decrease the concentration of process gas in a zone of thesubstrate through timing of the opening and closing of the fast actingvalves 120. Furthermore, by averaging the open times for the individualfast acting vales 120, a profile for the concentration of the processgas may be attained and modified during the processing operation. Theprocess gas may be pulsed into each zone individually in a sequence thatresults in the desired time average split, by cycling the fast actingvalves 120. For example, if a 60 percent/40 percent center to edge splitis desired, the fast acting valves 120 could continuously repeat 600milliseconds to the center fast acting valve, i.e. fast acting valve120-5, then 400 millisecond to the edge valves, i.e. fast acting valve120-1-120-4, during the process step. If the time for gas to come toequilibrium in the chamber is about 1 second, it is easy to imagine thisis similar to a continuous split in the flow along each of therespective gas passageways 185. Even if the equilibration time is muchshorter, as long as an integral number of pulse sequence periods arecompleted during the step, the desired uniformity control may beobtained. Additionally, with the substantially similar high conductancefor each of the gas passageways 185, the time to remove one gas andintroduce a new gas can be greatly shortened.

The operation of the gas delivery assembly 180 is further described withreference to FIG. 3. FIG. 3 is a block diagram for a method 300 forprocessing a substrate. The processing gasses may perform variousprocesses on the substrate. In a first embodiment, the process gasetches the substrate.

Method 300 begins at block 310 by injecting process gas into aprocessing chamber proximate an edge of a substrate disposed in theprocessing chamber through the first nozzle position at a firstlocation. The injection of the process gas is performed by the nozzlehaving its associated fast acting valve in an open position. The nozzlemay be oriented to inject the process gas in a direction radially inwardtoward the top surface of the substrate similar to the first nozzle inFIG. 2. Alternately, or in addition, the nozzle may be positioned toinject the process gas downward toward the top surface of the substratesimilar to the fifth nozzle in FIG. 2. In one embodiment, the nozzlesdisposed near the edge of the substrate are configured to inject processgas in a direction substantially parallel to the substrate. The gaspassageways may have high conductance to prevent chocking of the processgas flow. Each gas passageway has a substantially similar conductance.Thus, choke points or orifices are not needed and not a part of the gasdelivery assembly. The timing that the valve is open to allow flowthrough the nozzle controls the amount of gas provided to an area of thesubstrate exposed to the process gas from the first location. In oneembodiment, the process gas injected from the first location may flowsacross the center portion of the substrate. While the gas is flowingfrom the first location, no other gas flows from other locations.

Method 300 continues at block 320 by injecting the process gas into theprocessing chamber proximate the edge of the substrate disposed in theprocessing chamber from a second location while no gas is injected fromthe first location or other nozzle locations. The process gas injectedfrom the second location may flow beyond a center portion of thesubstrate. Thus, the process gas injected from the second location mayoverlap the extent of the substrate which was previously flowed by theinjection of process gas from the first location.

At block 330, the substrate is processed in the presence of theprocessing gas injected from the first and second location. Theprocessing of the substrate may be accomplished by averaging the timesfor the separate injections of the process gas from the first locationand the second location for determining a concentration of the processesgas across areas, or zones, of the substrate for processing thesubstrate.

The method 300 may include additional operations. For example, theprocess gas may be injected by a third nozzle into the processingchamber proximate the edge of the substrate from a third location whilegas is not injected from the first location, the second location, orother location. Additionally, the process gas may be injected into theprocessing chamber proximate the edge of the substrate disposed in theprocessing chamber from a forth location while no gas is injected fromthe first, second, third, or other location. The flow of the process gasthrough each of the nozzles may be substantially the same, e.g. thefirst and second nozzles, and third and fourth nozzles in suchconfigurations, are substantially the same. Thus, the concentrations forthe process gas can be tuned by cycling the injection of the process gasfrom one or more locations. The concentration of process gas indifferent zones of the substrate may be determined by the average timefor injecting the process gas from each of the nozzles.

Additionally, the process gas may be injected through the fifth nozzleinto the processing chamber proximate a center of the substrate disposedin the processing chamber from a fifth location while no additional gasis injected from the locations along the edge. In yet other embodiments,the processing chamber may have more than three nozzles and the centerinjection is performed while no process gas is injected into theprocessing chamber from any nozzle other than the center nozzle. Thecenter injection, or fifth nozzle shown in FIG. 2, may be equidistantfrom the first nozzle, second nozzle, or third nozzle the fourth nozzle.The center zone relative to other zones may be exposed to more or lessprocess gas for attaining azimuthal control, or center to edge control,where the concentration of the process gas at all the edges are equal.

A tuning gas may be provided to any one of the locations from a tuninggas source coupled through a mass flow controller (MFC). The mass flowcontroller may have a cycle time similar to the fast acting valve at thelocation of the intended injection of the tuning gas. The tuning gas maybe provided to the gas manifold by the MFC in a quantity similar to thatwhich would flow through the timed opening of the fast acting valve forthe nozzle at the intended location for the tuning gas. The tuning gasmay be supplied to the intended location with or without additionalprocess gas in the manifold.

In addition to averaging the time for injecting from the locationsproximate the edge of the substrate the nozzles at the respectivelocations may be sequenced. In one embodiment, injecting the processinggas from each of the nozzles may proceed in a sequential repetitivepattern. In another embodiment, injecting the processing gas from eachof the nozzles may proceed in a clockwise or counter-clockwise pattern.Alternately, the sequence for injecting the process gas may be patternedto achieve a processing effect, such as uniformity of etch. Theinjection sequence for the nozzles may be timed to extend the processinggas injected from each of the nozzles, disposed proximate the edge ofthe substrate, past a center of the substrate. The total time in whichthe process gas is injected from all of the nozzles may be performed inless than about 1 second.

Advantageously, the gas delivery assembly simplifies gas injection tothe processing chamber. The gas delivery assembly reduces thereal-estate for the gas system and the overall cost of the gas system.Additionally, the gas delivery assembly advantageously is tunable toextend into the center portion of the substrate to prevent dead zonesfor the processing gas. Thus, better uniformity for the substrate isachieved at a lower cost,

While the foregoing is directed to embodiments of the present invention,other and further embodiments of the invention may be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

What is claimed is:
 1. A method for processing a substrate comprising:flowing a first gas out from a gas panel through a mass flow controllerinto a manifold; injecting the first gas from the manifold through afirst nozzle in a first direction substantially parallel to a substratetoward a center of a processing chamber from proximate an edge of thesubstrate disposed in the processing chamber; timing the mass flowcontroller to coincide with the injecting of the first gas to determinewhen to flow a second gas out from the gas panel through the mass flowcontroller into the manifold while injecting the first gas; injectingthe second gas from the manifold through a second nozzle in a seconddirection substantially parallel to the substrate toward the center ofthe processing chamber from proximate the edge of the substrate disposedin the processing chamber while the first gas is not injected from thefirst location; controlling a time average for injections of the firstgas from the first nozzle and the second gas from the second nozzle tocontrol a concentration of the first and second gases across thesubstrate; and processing the substrate in the presence of the first andsecond gases injected from the first and second nozzles.
 2. The methodof claim 1 further comprising: injecting a third gas into the processingchamber proximate a center of the substrate disposed in the processingchamber from a third location coupled to the manifold while neither thefirst gas nor the second gas is injected from the first location or thesecond location.
 3. The method of claim 2 further comprising: providinga greater amount of a tuning gas from the manifold to the first locationthan the tuning gas provided from the manifold to the second location.4. The method of claim 3, wherein the amount of the tuning gas providedto the center is different than the amount of the tuning gas provided atthe edge of the substrate.
 5. The method of claim 1 further comprising:averaging the times for the separate injections of the first gas fromthe first location and the second gas from the second location, whereinthe average time for the injection from the first location is greaterthan the second location.
 6. The method of claim 1 further comprising:injecting a third gas into the processing chamber proximate the edge ofthe substrate disposed in the processing chamber from a third locationwhile neither the first gas nor the second gas is injected from thefirst location or the second location; and injecting the third gas intothe processing chamber proximate the edge of the substrate disposed inthe processing chamber from a fourth location while neither the firstgas, the second gas nor the third gas is injected from the first, secondor third location.
 7. The method of claim 1, wherein the processing thesubstrate comprises: etching the substrate.
 8. The method of claim 1,wherein the first gas injected from the first location is the same asthe second gas injected from the second location and creates anazimuthal distribution of the first and second gases across thesubstrate.
 9. A method for processing a substrate in a processingchamber having a plurality of spaced apart off center nozzles, themethod comprising: flowing a first process gas out from a gas panelthrough a mass flow controller into a gas manifold for a first quantitysimilar to that would flow through a first nozzle; a) injecting thefirst process gas from the gas manifold through the first nozzle intothe processing chamber proximate an edge of the substrate andsubstantially parallel to the substrate toward a center of theprocessing chamber; a1) timing the mass flow controller to coincide withthe injecting of the first process gas to determine when to flow asecond quantity of a second process gas out from the gas panel throughthe mass flow controller into the gas manifold while injecting the firstprocess gas; flowing the second quantity of the second process gas outfrom the gas panel through the mass flow controller into the gasmanifold while injecting the first process gas, wherein the firstprocess gas and second process gas are different; b) injecting thesecond quantity of the second process gas from the gas manifold througha second nozzle into the processing chamber proximate the edge of thesubstrate and substantially parallel to the substrate toward a center ofthe processing chamber while the first process gas is not injected fromthe first nozzle; flowing a third quantity of a third process gas outfrom the gas panel through the mass flow controller into the gasmanifold while injecting the second process gas; c) injecting the thirdquantity of the third process gas from the gas manifold through a thirdnozzle into the processing chamber proximate the edge of the substrateand substantially parallel to the substrate toward a center of theprocessing chamber while neither the first gas nor the second gas isinjected from the first nozzle or second nozzle; flowing a fourthquantity of a fourth process gas out from the gas panel through the massflow controller into the gas manifold while injecting the third processgas; d) injecting the fourth quantity of the fourth process gas from thegas manifold through a fourth nozzle into the processing chamberproximate the edge of the substrate and substantially parallel to thesubstrate toward a center of the processing chamber while neither thefirst process gas, the second process gas nor the third process gas isinjected from the first nozzle, second nozzle, or third nozzle; andsequentially repeating a, b, c and d to control a concentration of thefirst through fourth process gases across the substrate by timeaveraging each of a, b, c and d wherein each of a, b, c and d have asubstantially similar conductance for the process gas.
 10. The method ofclaim 9 further comprising: injecting a fifth process gas into theprocessing chamber proximate a center of the substrate from the manifoldthrough a fifth nozzle equidistant from the first nozzle, the secondnozzle, the third nozzle, and the fourth nozzle, while neither the firstprocess gas, the second process gas, the third process gas, nor thefourth process gas is injected from the first nozzle, the second nozzle,the third nozzle, and the fourth nozzle.
 11. The method of claim 9,wherein sequencing comprises: injecting the first process gas, secondprocess gas, third process gas and fourth process gas from each of therespective first nozzle, second nozzle, third nozzle, and fourth nozzlein a clockwise pattern or in a counter clockwise direction.
 12. Themethod of claim 9 further comprising timing the injection sequence forthe first through fourth nozzles to extend the first process gas, secondprocess gas, third process gas and fourth process gas injected from eachof the respective first nozzle, second nozzle, third nozzle, and fourthnozzle, disposed proximate the edge of the substrate, past a center ofthe substrate.
 13. The method of claim 12, wherein the sequencing ofinjecting the first process gas, second process gas, third process gasand fourth process gas from each of the first, second, third and fourthnozzle is performed in less than about 1 second.
 14. The method of claim12, wherein a flow of the first process gas, second process gas, thirdprocess gas and fourth process gas through each of the first, second,third and fourth nozzle is substantially the same.
 15. The method ofclaim 9, further comprising determining a split of process gas flow inthe processing chamber by averaging the time for injecting the firstprocess gas, second process gas, third process gas and fourth processgas from each of the first nozzle, second nozzle, third nozzle, andfourth nozzle.